Thrust-bearing.



N0. 676,769. Patented lune I8, l90ll.

6.6. PRATT. THRUST BEARING.

(Application 6166 Jan. 15, 1898.) (No Model.)

Fig. 1-

Witnesses: Inventor;

W J35 Azzurney TATES .NTTnlo PATENT Triton,

CHARLES R. PRATT, OF MONTCLAIR, NEW JERSEY, ASSIGNOR TO THE SPRAGUEELECTRIC COMPANY, OF NEW JERSEY.

THRUST BEARING.

SPECIFICATION forming part of Letters IPatent No. 676,769, dated June18, 1901. Application filed January 15,1898. Serial No. 666,739. (Nomodel.)

To (0Z5 whom it may concern.-

Be it known that I, CHARLES R. PRATT, a citizen of the United States ofAmerica, and a resident of Montclair, county of Essex, and State of NewJersey, have invented certain new and useful Improvements in Thrust-Bearings, of which the following is a specification.

The invention consists in providing between the stationary thrust-plateand the revolving thrust-plate cylindrical rollers which are caged inholes cut through an intermediate plate, herein called a cage-plate, theholes being so placed that the rollers will lie with their axes ofrotation on radii of the shaft and preferablylie in one or more spirals,so that the paths of the faces of the cylinders shall overlap.

In the accompanying drawings, which form a part of this specification,Figure 1 is a crosssectional view of my improved bearing on a verticalplane passing through the axis of the shaft, the shaft itself beingshown in elevation. Fig. 2 is an end and side view of one of thecylindrical rollers. Fig. 3 is a front view of the cage-plate.

The shaft A, along which the thrust acts in the direction indicated bythe arrow, is journaled in a bushing in a bearing-block V. This block isa flanged cylinder-head which fits into an opening in framework W,mounted upon a suitable base. The shaft is provided with a threaded end,onto which a nut B is screwed and keyed fast. This nut bears against athrust-block C, the two forming a balland-socket joint. The revolvingthrustplate N, the stationary thrust-plate T, and the intermediatecage-plate P, with its rollers It, lie between the thrust-block C andthe bearing-block V, separating them, as shown. A plate of lead or othersuitable soft material L is interposed between the revolving thrustplateN and the shaft A and the thrust-block C. A similar plate L lines thecavity in the bearing-block V, into which the stationary thrust-plate Tfits.

The cage-plate P is provided with holes, in which the rollers R arecaged. These holes are shown in Fig. 3 as laid off in two spirals, whichare started at the two opposite ends of a diameter. The thrust oroutward crowding of each roller is therefore balanced by the thrust of acorresponding roller on the opposite side, and the rollers being inspirals they are at different and graded distances from the axis of thehearing, so that the wear will be distributed over the entire surface ofthe thrust-plates. Outside of the outer holes and continuing each of thespirals are two lugs g g on each side of the cage-plate to keep itproperly positioned between the thrust-plates. Each roller is held toits own circular path and with its axis radial to the axis of the mainshaft, so that its natural path of rotation will always be tangent tothe circles on which it travels on the two thrust-blocks at the point ofcontact, and thisis accomplished by merely caging each roller betweenthe four flat walls of rectangular holes in the cageplate and relying onthe flat ends of the rollers for the purpose without the use oftrunnions or other guides for the rollers. The omission of trunnionspermits the rollers to adjust themselves freely to the surfaces ofthethrust-plates.

Mechanical difficulties have heretofore prevented the employment ofcylindrical rollers between the parallel faces of thrust-plates, owingto the fact that the inner and the outer edges of the rollers mustrevolve at the same speed, although they travel on circles of differentdiameter. There is consequently a slippage at one orboth edges. Indeveloping this invention it has been found that this slippage is not ofconsequence with rollers traveling in circles of four inches in diameterand over if the tread is narrowed to about five thirty-seconds of aninch. In practice it is found convenient to make the rollers under theabove conditions of one-half inch diameter and one-quarter of an inchwide, the corners being rounded to secure the narrow tread. The rollersare cut from cold-drawn tool-steel and are case-hardened.

What I claim, and desire to secure byLetters Patent of the UnitedStates, is-- 1. A thrust-bearing comprising a main shaft, thrust plates,cylindrical rollers between the thrust-plates, and a cage-plate by whichthe rollers are positioned in spirals in balanced relation to eachother, substantially as described.

- rally-arranged holes therein, and the thrustplates being separated byshort cylindrical rollers caged in the holes in the cage-plate Withoutthe use of trnnnions, the axes of the r5 rollers being radial to theshaft, substantially as described.

Signed by me at New York city this 13th day of January, 1898.

CHAS. R. PRATT.

\Vitnesses:

THOMAS EWING, J r., SAMUEL W. BALCH.

